1. Field of the Invention
This invention relates to a hubcap and more particularly to a vented plug which may be inserted into a hubcap for use with automatic bearing lubrication systems.
2. Background Information
Hubcaps are used on wheels of many trucks and trailers to prevent contaminants from entering the wheel bearings and for maintaining the oil or grease in the bearings. In regent years, Dual Dynamics, Inc. of Lincoln, Nebr. has designed a hubcap having an automatic bearing lubrication system. The hubcap of Dual Dynamics, Inc. is known as a Dual-Guard.TM. hubcap and includes a hubcap which may be mounted on the studs of the truck or trailer wheel or threaded onto some types of axles. The interior of the Dual-Guard.TM. hubcap is filled with oil or grease so that the wheel bearings are lubricated. Heretofore, it has been necessary to provide a small vent opening in the Dual-Guard.TM. hubcap to permit the venting of excessive pressure within the hubcap as the bearings become heated. Although the vent openings work extremely well, they do pose a problem in certain situations. For example, in some dock loading situations, the wheels of the truck move downwardly into an excavated area adjacent the dock so that the bed of the truck will be level with the dock. In some cases, the excavated area adjacent the dock may be filled with water. Should the hubcaps of the truck wheels be submerged in the water, water and other contaminants may enter the interior of the hubcap through the vent opening. Further, water may enter the interior of the hubcap through the vent opening when the truck or trailer is power washed. The water and contaminants may dramatically shorten the life of the wheel bearings, hub and axle of the truck.
The problems associated with the prior art were solved by way of the disclosure in U.S. Pat. No. 5,192,117 wherein a hubcap is described which includes a vent opening having a plug positioned therein which is comprised of a bronze powder material cast into a cylindrical shape and press-fitted into the vent opening to permit the continuous passage of air therethrough to vent the wheel bearings but which prevented the passage of water and other contaminants therethrough.
In one form of a prior art hubcap, a Neophrene.TM. plug having a vent opening formed therein is used to seal the interior of the hubcap to prevent the escape of lubricant therefrom. While the vented Neophrene.TM. plug of the prior art does provide a convenient means for inserting lubricant into the hubcap, a contaminant such as water or the like may enter the interior of the hubcap through the vent opening in the plug.
It is therefore a principal object of the invention to provide an improved hubcap.
A further object of the invention is to provide a hubcap having a removable Neophrene.TM. plug including an insert (vent) molded therein which permits air to pass therethrough to vent the hubcap but which prevents water and other contaminants from passing therethrough.
It is a further object of the invention to provide a Neophrene.TM. plug for a prior art hubcap wherein the Neophrene.TM. plug has a metal insert molded therein which permits air to pass therethrough to vent the hubcap but which prevents water and other contaminants from passing therethrough.
These and other objects will be apparent to those skilled in the art.